Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
  • B09C—RECLAMATION OF CONTAMINATED SOIL
  • B09C1/00—Reclamation of contaminated soil
  • B09C1/02—Extraction using liquids, e.g. washing, leaching, flotation

Definitions

• the invention relates to a method for the treatment of contaminated soil according to the preamble of the main claim.
• the purpose of the method according to the invention is to process contaminated soil, especially from coking plants or plants with similar products.
• the post-published P 34 47 079 also relates to a method for the thermal treatment of contaminated earth, wherein the earth is treated at temperatures of at least 600 ° C and the resulting gas is also burned.
• DE-OS 25 31 732 describes a process for the removal, treatment or regeneration of oil-contaminated soil, the oil or the water-soluble pollutant components being washed out with relaxed hot water, preferably at temperatures between 60 and 90 ° C.
• the shredded cleaning material is thoroughly mixed with the cleaning medium in a screw drum and then separated from the contaminant-binding cleaning medium by settling in a clarifier.
• a similar process for regenerating soil contaminated especially by oil. is known from DE-OS 27 24 271.
• the contaminated earth after possible crushing with a liquid, e.g. As water, slurried and heated to evaporation temperature in a flow chamber.
• the top layer of the slurry should be stripped off in the flow chamber. It has been shown that the substances described in the introduction can be washed out of the contaminated soil only to a small extent or not at all in such a treatment with a temperature up to the evaporation temperature of the water.
• the object of the invention is now to propose a method for the treatment of contaminated soil, in which on the one hand the elaborate thermal treatment at temperatures of at least 600 ° C can be dispensed with and on the other hand also substances can be dissolved which in the above-mentioned slurrying up to the evaporation temperature of the water not yet be resolved.
• the residual C content of the earth treated in the extraction stages is significantly lower than in the case of pyrolysis of the earth at temperatures of more than 600 ° C.
• It can be a simple solvent, such as. B. water can be used.
• the solvent capacity of the contaminants can be increased by 180 ° C. 9. Due to the reversible effect of cooling the loaded solution, solvents and contaminants can be separated by simple decantation, ie, as with other processes, no further extraction steps are necessary.
• the inorganic pollutants are also dissolved as electrolytes, which can also be removed from the circulation by activating carbonization, stripping and reverse osmosis.
• the halogens released during the partial oxidation from the corresponding organic and inorganic pollutants can be removed from the cracked gas using known methods.
• the combustion of the pollutant-free residual gas of the POX is used in addition to the POX waste heat for further energy recovery and the CO 2 that forms can be used in the carbonation stage.
• the contaminated soil (1) is crushed in a homogenizer (2) and treated with the addition of circulating water (3) / (22) to a suspension (4) (up to 300 g / l).
• a liquid (8) and a solid phase (9) / (10) will form in the extractors (5) / (6) so that so-called separation effects occur.
• By switching on mechanical elements (stirrers) or suitable countercurrent cascades it is ensured that the solid phase is preserved as a flowable suspension.
• a drying system (12) drum or belt dryer
• the earth is separated from the residual water (13) to a residual moisture of approx. ⁇ 30% by weight.
• the soil (14) is mixed with biomass (16) (humus or similar) and the mixture is then stored in a so-called maturation or revitalization landfill (17) and after some time stands as processed soil (18) available again.
• the residual pollution of the earth mainly consists of hydrocarbon
• the residual degradation can be carried out by known, selectively working species.
• the contaminated hot water (8) / (26) of the extraction stage (5) is then cooled, reducing the solvency.
• the cooling (27) can be carried out in one or more stages, so that, if appropriate, different oil fractions (32) can be drawn off from the subsequent separators (30).
• a carbonation stage (24) can also be installed, where with z. B. CO 2 -containing flue gas (28) a part of these substances (25), for. B. Al 2 O 3 , SiO 2 , is precipitated, which are usually present as colloidal solutions.
• These substances are e.g. B. mixed in the dryer (12) of the earth.
• the oily phase with organic products (32) is then converted into CO and H 2 using the partial non-catalytic oxidation (POX) (40) method using O 2 or hot air (41). Because of the reducing atmosphere, by-products such as HCl, H 2 S, COS and traces of NH 3 and HCN are formed, which can be removed from the cracked gas using known processes.
• POX partial non-catalytic oxidation
• the gas is then burned.
• the energy (44) obtained in the cooler (43) from the waste heat (42) of the POX (40) and the energy (44) obtained during combustion (53) is used for heating (19) / (20) the streams of the extraction (5) / (6 ) and / or directly as a drive for mechanical devices.
• Vapors with H 2 S, NH 3 and HCN (35) are optionally separated from the aqueous phase (31) in a stripper (33) with the addition of direct steam (34).
• Part of the circulating water (36) is processed into so-called pure water using the membrane processes CFF and RO (37).
• the concentrate (38) is added to the circulating water stream (3) in a halogen absorber (46). Otherwise, the concentrate (38) can also be added as a moderator to the oily phase of the POX (40).
• Part of the pure water obtained after the reverse osmosis (37) is taken up in a direct cooler (49) with the exhaust gas (48) from the halogen absorber (46).
• CFF Cross-Flow Filtration
• RO Reverse Osmosis
• Halogen absorber (approx. 250 ° C)

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Soil Sciences (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Processing Of Solid Wastes (AREA)
• Separation Using Semi-Permeable Membranes (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

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Cited By (5)

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Citations (7)

Family Cites Families (8)

• 1986
  • 1986-10-03 DE DE19863633699 patent/DE3633699A1/de active Granted
• 1987
  • 1987-10-02 WO PCT/EP1987/000568 patent/WO1988002285A1/de not_active Ceased
  • 1987-10-02 EP EP87906421A patent/EP0329661B1/de not_active Expired - Lifetime
  • 1987-10-02 US US07/346,993 patent/US4993873A/en not_active Expired - Fee Related

Patent Citations (7)

Non-Patent Citations (1)

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